The present invention relates to subterranean operations and, more particularly, to methods of using relative permeability modifiers for the diversion of aqueous fluids during subterranean operations.
The diversion of treatment fluids in subterranean operations is well known and may be desirable in a variety of subterranean operations, such as acid stimulation operations, injection operations, scale inhibition operations, and clay stabilization operations. In many instances, diversion is desirable because the treatment fluid may preferentially enter portions of a subterranean formation with high permeability at the expense of portions of the subterranean formation with lesser permeability. For example, in acid stimulation operations, it may be desired to contact less permeable portions of the subterranean formation with the treatment fluid containing an acid so as to achieve the desired stimulation. In scale inhibition operations and clay stabilization operations, it may be desirable to divert the treatment fluid so as to obtain a uniform distribution of the treatment fluid throughout the subterranean formation regardless of the permeability of the particular portion thereof. In some instances, these high-permeability portions of the subterranean formation may be watered-out zones, which predominately produce water rather than the desired hydrocarbons.
A variety of techniques have been used to divert treatment fluids to less permeable portions of a subterranean formation. Such techniques have involved, among other things, the injection of particulates, foams, or blocking polymers (e.g., crosslinked aqueous gels) into the subterranean formation so as to plug off the high-permeability portions of the subterranean formation, thereby diverting subsequently injected fluids to less permeable portions of the subterranean formation. While each of these diversion techniques has been used successfully, there may be disadvantages. In some instances, plugging off the high-permeability sections may not be suitable for a producing formation, for example, because the injected solution (or material) may reduce or stop the flow of hydrocarbons in addition to the achieving a desired diversion of the treatment fluid. Therefore, to return the formation to production, expensive and/or time-consuming remedial treatments may be required to remove the injected solution (or material). Furthermore, techniques geared toward injecting solutions (or materials) designed to plug off high-permeability portions of the subterranean formation may require expensive zonal isolation, which may be inaccurate, leading to inadvertent plugging of and/or damage to the hydrocarbon-bearing sections.